Visible from outer space, the World Heritage-listed Great Barrier Reef is one of the largest living structures on the planet.
In 1975 the Great Barrier Reef Marine Park was established to protect its fragile ecosystems, which include more than 3,000 coral reefs; 600 continental islands, including the beautiful Whitsunday group; 300 coral cays; and inshore mangrove islands.
One of the seven wonders of the natural world, the park stretches for 2,300 km along the state of Queensland, on Australia's east coast (that's about the distance between Mexico and Vancouver). Diving and snorkeling are spectacular. The astounding array of marine life includes soft and hard corals, more than 1,600 species of tropical fish, sharks, dugongs, dolphins, turtles, rays, and giant clams.
Those who prefer to stay dry can view the reef from underwater viewing stations and glass bottom boats. On the mainland, Cairns, Port Douglas, and Airlie Beach are the main launching points for tours.